Are your headphones or earplugs giving you problems. Don't throw them out yet. You can repair them yourself with this instructable. There are only three main problems which occur with headphones. They are

Damaged 3.5mm pin
Damaged wires
Damaged speakers

Step 1:

If your headphones are damaged in any way you don't need to worry. Jumper1111 is here. All you need to do is replace the pin. First you will need to buy a new 3.5mm pin. Then cut out the old 3.5mm pin. There should be a total of 4 wires inside. There should be 2 wires of the same color they are both negative. The other two wires are positive for left and right speakers. If there aren't any wires but kind of threads you don't need to worry. They are wires also but enamel is covering them. If you want to expose the wire just burn those thread like wires a little and then rub them lightly with  sandpaper. Well this should expose the copper of the wire.
have you ever tried using an oscilloscope to figure out where the problem is?
I live in india and there are no oscilloscope available. I can't buy them online because the shipping would cost too much and I can't afford that coz I'm just 13. But your idea is good.